if (!leakDetectionEnabled) {
            return;
        }

        // Process phantom references to detect leaks
        Reference<?> ref;
        while ((ref = referenceQueue.poll()) != null) {
            handlePhantomReference(ref);
        }

        // Check for old unclosed resources
        long now = System.currentTimeMillis();

int maxDepth = -1               // Max depth (-1 = unlimited)
long maxAccessCount = 0         // Max URLs (0 = unlimited)
```

### CrawlerThread (`CrawlerThread.java`)

Worker thread for crawling.

**Flow**: Poll URL → Validate → Get client → Delay → Check last-modified → Execute → Process → Extract children → Queue children → Delay

### CrawlerClientFactory

Pattern-based client selection using `LinkedHashMap<Pattern, CrawlerClient>`.

    }

    @Override
    public synchronized Map<String, Object> read() {
        while (!isFinished.get() && queue.isEmpty()) {
            addDocumentToQueue();
        }

        return queue.poll();
    }

    @Override
    public void close() {
        isFinished.set(true);
        queue.clear();
    }

    /**
     * Sets the scroll size.
     * @param scrollSize The scroll size.

            UrlQueue urlQueue;
            while ((urlQueue = urlQueueService.poll(sessionId1)) != null) {
                assertTrue(urlQueue.getUrl().startsWith(url1));
            }
            while ((urlQueue = urlQueueService.poll(sessionId2)) != null) {
                assertTrue(urlQueue.getUrl().startsWith(url2));
            }

            }
        }
    }

    static MyToken getNextUniqueToken(final PriorityQueue<MyToken> que, final MyToken prev) {
        while (true) {
            final MyToken token = que.poll();
            if (token == null) {
                return null;
            }
            if (prev == null || !prev.identical(token)) {
                return token;
            }
        }
    }

    }

    // ===================================================================================
    //                                                                           Roll-back
    //                                                                           =========
    @Override
    public void rollback() {
        for (MultipartFormFile formFile : elementsFile.values()) {

        },
        "italian_elision": {
          "type":         "elision",
          "articles": [
                "c", "l", "all", "dall", "dell",
                "nell", "sull", "coll", "pell",
                "gl", "agl", "dagl", "degl", "negl",
                "sugl", "un", "m", "t", "s", "v", "d"
          ]
        },
        "italian_stop": {
          "type":       "stop",

        }
        this.toRemove.add((SmbTransportImpl) trans);
    }

    private void cleanup() {
        SmbTransportImpl trans;
        while ((trans = this.toRemove.poll()) != null) {
            if (log.isDebugEnabled()) {
                log.debug("Removing transport connection " + trans + " (" + System.identityHashCode(trans) + ")");
            }
            this.connections.remove(trans);

        });

        Thread reader = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    statusSetLatch.countDown();
                    // Poll for status change instead of fixed sleep
                    long startTime = System.currentTimeMillis();
                    while (System.currentTimeMillis() - startTime < 500) {

            requestQueue.offer(new CrawlRequest(url, 0));
            while (!requestQueue.isEmpty() && (maxAccessCount < 0 || counter < maxAccessCount)) {
                final CrawlRequest crawlRequest = requestQueue.poll();
                if ((maxDepth != -1 && crawlRequest.getDepth() > maxDepth) || processedUrls.contains(crawlRequest.getUrl())) {
                    if (logger.isDebugEnabled()) {